<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
<script>
  class Parent{
    constructor(name,age){
      this.name = name
      this.age = age
    }
    setName(){
      console.log(`${this.name}-parent`);
    }
    say(){
      console.log('say');
    }
  }
  class Child extends Parent{
    constructor(name){
      super()
      this.name = name
    }
    setName(){
      console.log(`${this.name}-child`);
    }
  }
  // new Parent('ls').setName()
  new Child('zs').setName()
  new Child().say()
</script>
</body>
</html>